Fluids are often stored in vessels from which they are intermittently dispensed. Fluids include chemical compositions some of which are vulnerable to oxidation upon prolonged contact with air present in the environment. Some fluids are chemical compositions which include volatile organic components which have a tendency to evaporate or otherwise escape from containers in which they are stored and from which they are dispensed. There is a continual need for ways to reduce fluid exposure to air.
World Intellectual Property Organization (W.I.P.O.) Patent Application Number WO0240122A2 and U.S. Pat. No. 7,000,806 each disclose a dispenser for dispensing a fluid that includes a rigid vial with a main fluid chamber containing a fluid, and a pump assembly that is in fluid communication with the main fluid chamber and is configured to dispense a predetermined quantity of fluid from the main fluid chamber. A flexible bladder is provided which is located within the main fluid chamber and is configured to expand to fill the ullage created within the main fluid chamber during dispensing of fluid by the pump assembly. The resilient bladder tends to force itself outwardly toward the rigid vial and, in turn, increases the pressure within the main fluid chamber in comparison to the interior of the bladder to thereby prevent the ingress of air or vapors through the bladder or otherwise into the main fluid chamber.
U.S. Pat. No. 4,817,830 discloses an improved thin-walled pressure vessel having a bladder therein. This vessel includes a shell having an opening and a spout disposed around the opening. An improved cap normally closes this opening, secures the bladder to the shell of the vessel, and provides communication between the outside of the vessel and the inside of the bladder. The cap member comprises a main body member having an opening which receives a valve member. This valve member extends out through one end of the cap member. It also extends through the opposite end of the cap and into the bladder through an opening in the bladder. The valve member engages a portion of the bladder around the opening and clamps this portion against the main body member to secure the bladder to the cap member. As the pressure in the bladder increases, it forces the valve member further against the walls of the opening in the main body member, increasing the clamping force to firmly secure the bladder to the cap member.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.